A precise positioning method for thin-walled cabin section parts

Abstract

The present application relates to a kind of thin-walled cabin section class parts accurate positioning method, belong to part processing technical field, solve the problem that in prior art, for the part of large shape surface deformation and without machining allowance, cannot ensure the accuracy of processing reference point.The method includes: based on the plane ABC, plane DEP and plane FGQ constructed on the three-dimensional model of part, construct three-dimensional coordinate system XYZ for part processing, and find the part alignment;Plane DEP and plane FGQ are handled, and new plane D' E' P' and plane F' G' Q' are constructed;With the intersection of plane ABC, plane D' E' P' and plane F' G' Q' as zero point U, and based on the normal vector a, b, c of plane ABC, plane DEP and plane FGQ, new three-dimensional coordinate system X' Y' Z' is constructed;Wherein, with three-dimensional coordinate system X' Y' Z' as three-dimensional coordinate system for part processing.Accomplished in the case where the shape of part is deformed relatively large, can be more accurate to the part positioning.

Description

Technical Field

[0001] This invention relates to the field of parts processing technology, and in particular to a method for precise positioning of thin-walled compartment-type parts. Background Technology

[0002] A certain compartment-type cold-form part structure includes a hollow body with an irregular surface. Two clamps are located on one end face of the body, serving as the part's fixing components. This part is 3D printed, leaving no machining allowance after printing, but requires further machining after completion.

[0003] Before machining, the compartment needs to be scanned and scribed to determine the machining datum. Currently, the machining datum is generally determined by scribing by a fitter. However, for parts with large surface deformation and no machining allowance, the scribing needle has large errors in different areas when measuring the chuck, requiring repeated adjustments to the parts.

[0004] In summary, the existing method of determining machining datum by scribing by fitter is inconvenient and cannot guarantee the accuracy of the machining datum. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a precise positioning method for thin-walled compartment-type parts, in order to solve the problem that existing methods cannot ensure the accuracy of machining datum for parts with large surface deformation and no machining allowance.

[0006] On one hand, embodiments of the present invention provide a method for aligning thin-walled compartment-type parts, including:

[0007] Step 1: Based on the planes ABC, DEP, and FGQ constructed on the 3D model of the part, construct and establish a 3D coordinate system XYZ for part machining, and align the part.

[0008] Step 2: Perform midpoint processing on plane DEP and plane FGQ to construct new planes D′E′P′ and F′G′Q′;

[0009] Step 3: Using the intersection point of planes ABC, D′E′P′, and F′G′Q′ as the origin U, and based on the normal vectors a, b, and c of planes ABC, DEP, and FGQ, construct a new three-dimensional coordinate system X′Y′Z′.

[0010] Among them, the three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part machining.

[0011] Furthermore, step 1 includes:

[0012] S101: Mill three planes A, B, and C on one end face of the part;

[0013] S102: Mill four planes D, E, F, and G on the chuck of the part;

[0014] S103: Take a point on the part as the zero point O, and based on the zero point O, scan the part to establish a theoretical three-dimensional coordinate system XYZ in the three-dimensional model of the part.

[0015] S104: In the 3D model, construct plane ABC based on the center points of three planes A, B, and C, and obtain the angular offset α of the normal vector a relative to the Z-axis of the theoretical 3D coordinate system XYZ based on the normal vector a of plane ABC.

[0016] S105: Based on the angular offset α, adjust the position of the part on the CNC machine tool until the normal vector a coincides with the Z-axis of the theoretical three-dimensional coordinate system XYZ;

[0017] S106: In the 3D model, construct a new plane DEP based on planes D and E, and construct a new plane FGQ based on planes F and G;

[0018] S107: In the 3D model, based on the normal vectors b and c of plane DEP and plane FGQ, obtain the angles β and γ between normal vectors b and c and normal vector a, respectively, and adjust plane DEP and plane FGQ so that β and γ are 90°.

[0019] Furthermore, step 2 includes:

[0020] S201: Obtain the distance d between the two X reference planes of the first chuck;

[0021] S202: Using the center point of plane D as the detection zero point and the center point of plane F as the measurement point, the distance e from plane F to the zero point is detected and obtained using the probe on the CNC machine tool;

[0022] S203: Obtain the difference between e and 1 / 2d, and determine the center point offset difference f of plane D;

[0023] S204: Based on the offset difference f, adjust the position of plane DEP to obtain plane D′E′P′;

[0024] S205: Obtain the distance r between the two Y-reference planes of the first and second chucks;

[0025] S206: Using zero point O as the detection zero point, on the first chuck, with the point on the Y reference plane 4 where the non-plane D is located as the detection point, the distance s between the detection point and the detection zero point is detected and obtained using the probe on the CNC machine tool;

[0026] S207: Obtain the difference between s and 1 / 2r, and determine the offset difference t of the zero point O;

[0027] S208: Based on the offset difference t, adjust the position of plane FGQ to obtain plane F′G′Q′.

[0028] Furthermore, in step S204,

[0029] If f equals 0, then plane D′E′P′ coincides with plane DEP;

[0030] If f is greater than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f to obtain the plane D′E′P′.

[0031] If f is less than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f in a direction away from the plane, to obtain the plane D′E′P′.

[0032] Furthermore, in step S208, if t equals 0, then plane F′G′Q′ coincides with plane FGQ;

[0033] If t is greater than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F′G′Q′.

[0034] If t is less than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F′G′Q′.

[0035] Furthermore, in step S205, on the first chuck, the point on the Y-reference plane where the non-plane D is located is taken as the zero point, and on the second chuck, the point on the Y-reference plane where the non-plane E is located is taken as the detection point. The distance r between the two Y-reference planes is detected and obtained using the probe on the CNC machine tool.

[0036] Furthermore, step S102 includes:

[0037] S1021: Plane D and plane E are milled on the sides of the first chuck and the second chuck respectively, and plane D and plane E are parallel to the Y reference plane respectively;

[0038] S1022: Plane F and plane G are milled on the side of the first chuck, respectively, and plane F and plane G are parallel to the X reference plane.

[0039] Furthermore, plane D and plane E are located on the first chuck and the second chuck, respectively, and are arranged adjacent to each other; plane F and plane G are located on the two X reference planes of the first chuck, respectively.

[0040] Among them, the side surfaces corresponding to the two clamps and the side surfaces parallel to these surfaces are used as the Y-reference plane, and the direction perpendicular to the Y-reference plane is used as the actual X-axis direction based on the part.

[0041] Take any plane adjacent to the Y-reference plane as the X-reference plane, and take the direction perpendicular to the X-reference plane as the actual Y-axis direction based on the part.

[0042] Furthermore, in step S106, the center points of plane D and plane E are connected, a straight line DE is drawn, and an arbitrary plane DEP is constructed through the straight line DE.

[0043] Furthermore, in step S106, the center points of plane F and plane G are connected, a straight line FG is drawn, and an arbitrary plane FGQ is constructed through the straight line FG.

[0044] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0045] 1. In the process of constructing the three-dimensional coordinate system XYZ, the present invention adjusts the spatial position of the part to achieve the alignment of the part's position. Based on the relative position of the zero point of the constructed three-dimensional coordinate system XYZ with the part, the three-dimensional coordinate system is reconstructed. The reconstructed three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part processing, which overcomes the problem of the zero point O offset affecting accuracy and achieves precise positioning of the part.

[0046] 2. This invention mills three small planes on a part with significant external deformation. New planes are then constructed using these three small planes. By adjusting the spatial position of the part and the direction of the normal vector of the newly constructed planes, alignment is first achieved in the Z-axis direction of the theoretical coordinate system. Based on this, two new planes are constructed by milling four small planes at the chuck of the part. Alignment in the X-axis and Y-axis directions of the theoretical coordinate system is achieved using the normal vectors of these two new planes. Thus, even with thin wall thickness and no machining allowance, the part can be aligned on a CNC machine tool. Furthermore, based on a defined three-dimensional coordinate system for part machining, the influence of errors from manual scribing can be overcome, thereby improving the precision of part machining.

[0047] 3. This invention eliminates the traditional scribing method and eliminates the need to level the parts during the first processing step, greatly reducing the labor intensity of the operator.

[0048] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0049] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0050] Figure 1 This is a flowchart of the precise positioning method for thin-walled compartment-type parts in this invention;

[0051] Figure 2 This is a schematic diagram showing the positions of the three planes A, B, and C on the part in this invention;

[0052] Figure 3 This is a schematic diagram showing the positions of the Y-reference plane and the X-reference plane on the chuck in this invention;

[0053] Figure 4 This is a schematic diagram showing the positions of the four planes D, E, F, and G on the clamp in this invention;

[0054] Figure 5 This is a schematic diagram showing the position of zero point O on the part in this invention;

[0055] Figure 6 This is a schematic diagram showing the position of plane ABC when it is perpendicular to the Z-axis of the theoretical coordinate system in this invention.

[0056] Figure 7 This is a schematic diagram showing the relative positions of plane ABC, plane DEP, and plane FGQ in this invention;

[0057] Figure 8 This is a schematic diagram showing the relative positions of planes ABC, D′E′P′, and F′G′Q′ in this invention.

[0058] Figure label:

[0059] 1- The positions of the three planes A, B, and C on the part; 2- The X-axis direction perpendicular to the Y-reference plane; 3- The Y-axis direction perpendicular to the X-reference plane; 4- The Y-reference plane; 5- The X-reference plane; 6- The chuck; 601- The first chuck; 602- The second chuck; 7- The positions of the four planes D, E, F, and G on the chuck; 8- The position of the zero point O; 9- The position of the plane ABC perpendicular to the Z-axis of the theoretical coordinate system; 10- The position of the constructed plane DEP; 11- The position of the constructed plane FGQ; 12- The position of the zero point U; 13- The position of the constructed plane D′E′P′; 14- The position of the constructed plane F′G′Q′; 15- The part. Detailed Implementation

[0060] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0061] A certain compartment-like part structure includes a hollow body with an irregular surface. Two clamps are located on one end face of the body, serving as the part's fixing components. These clamps are generally symmetrically distributed on the part and have a cylindrical structure with four sides and a rectangular cross-section. Currently, this part is 3D printed, but the finished part has no machining allowance and requires further processing after completion.

[0062] Before machining, the compartment needs to be scanned and scribed to determine the machining datum. That is, the fitter uses a scribing needle to measure the area of ​​the chuck based on the scanning results and scribing the results as the datum for subsequent machining. However, since the deformation of the part's outer surface exceeds 0.8 and there is no machining allowance, and the surface of the chuck is rough, the scribing needle has a large error in different areas when measuring the chuck. The part needs to be adjusted repeatedly, which is inconvenient and cannot ensure the accuracy of the machining datum.

[0063] To address the above problems, this invention provides a method for precise positioning of thin-walled compartment-type parts, comprising:

[0064] Step 1: Based on the planes ABC, DEP, and FGQ constructed on the 3D model of the part, construct the 3D coordinate system XYZ for machining part 15, and align the part.

[0065] Step 2: Perform midpoint processing on plane DEP and plane FGQ to construct new planes D′E′P′ and F′G′Q′;

[0066] Step 3: Take the intersection of plane ABC, plane D′E′P′ and plane F′G′Q′ as the zero point U, and construct a new three-dimensional coordinate system X′Y′Z′ based on the normal vectors a, b and c of plane ABC, plane DEP and plane FGQ;

[0067] Among them, the three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part machining.

[0068] Compared with the prior art, the present invention adjusts the spatial position of the part during the construction of the three-dimensional coordinate system XYZ to align the part's position. Based on the relative position of the zero point of the constructed three-dimensional coordinate system XYZ with the part, the three-dimensional coordinate system is reconstructed. The reconstructed three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part processing, which overcomes the problem of the zero point O offset affecting accuracy and achieves precise positioning of the part.

[0069] Among them, such as Figure 6 As shown, the part is provided with two chucks, namely the first chuck 601 and the second chuck 602, which are used to fix the part 15 on the CNC machine tool or other processing device, and are the fixed clamping parts of the part.

[0070] The first clamp 601 and the second clamp 602 have the same structure. The first clamp 601 is a columnar structure with four sides.

[0071] Specifically, step 1 includes:

[0072] S101: Mill three planes A, B, and C on one end face of part 15;

[0073] Specifically, such as Figure 2-4 As shown, three planes A, B, and C are milled on one end face of the part where the chuck 6 is located;

[0074] The dimensions of the three planes A, B, and C are φ3mm-φ4mm.

[0075] S102: Mill four planes D, E, F, and G on the chuck 6 of the part;

[0076] Specifically, including:

[0077] S1021: Plane D and plane E are milled on the sides of the first chuck 601 and the second chuck 602 respectively, and plane D and plane E are parallel to the Y reference plane respectively.

[0078] Among them, the side surfaces corresponding to the two clamps and the side surface parallel to the two clamps are used as the Y reference plane, and the direction perpendicular to the Y reference plane is the actual X-axis direction based on the part.

[0079] Among them, plane D and plane E are located on the first chuck 601 and the second chuck 602, respectively.

[0080] Furthermore, planes D and E are set adjacent to each other.

[0081] Furthermore, connect the center points of plane D and plane E, and draw a straight line DE. At this time, the straight line DE is perpendicular to the central axis of the two clamps.

[0082] For example, the dimensions of plane D and plane E are both φ1mm-φ3mm.

[0083] S1022: Plane F and plane G are milled on the side of the first chuck 601, and plane F and plane G are parallel to the X reference plane.

[0084] Among them, any plane adjacent to the Y reference plane is taken as the X reference plane 5, and the direction perpendicular to the X reference plane 5 is taken as the actual Y-axis direction based on the part.

[0085] Among them, plane F and plane G are not on the same side of the first clamp.

[0086] Furthermore, connect the center points of plane F and plane G, and draw a straight line FG. At this time, the straight line FG is perpendicular to the central axis of the first clamp.

[0087] The dimensions of plane F and plane G are both φ1mm-φ3mm.

[0088] S103: Take a point on part 15 as zero point O, and scan the part based on zero point O to establish a theoretical three-dimensional coordinate system XYZ in the three-dimensional model of the part.

[0089] Among them, such as Figure 5 As shown, the position of zero point O satisfies the following conditions: it is on plane ABC and located in the spatial region corresponding to the inner cavity of part 15.

[0090] The theoretical three-dimensional coordinate system XYZ is kept consistent with the three-dimensional coordinate system of the CNC machine tool.

[0091] S104: In the 3D model, construct plane ABC based on the center points of three planes A, B, and C, and obtain the angular offset α of the normal vector a relative to the Z-axis of the theoretical 3D coordinate system XYZ based on the normal vector a of plane ABC.

[0092] S105: Based on the angular offset α, adjust the position of the part on the CNC machine tool until the normal vector a coincides with the Z-axis of the theoretical three-dimensional coordinate system XYZ;

[0093] In this process, after the position of part 15 is adjusted on the CNC machine tool, its actual position changes, thereby achieving the alignment of part 15 on the Z-axis of the theoretical three-dimensional coordinate system XYZ.

[0094] S106: In the 3D model, construct a new plane DEP based on planes D and E, and construct a new plane FGQ based on planes F and G;

[0095] In the 3D model, any plane DEP is constructed through the line DE; any plane FGQ is constructed through the line FG.

[0096] S107: In the 3D model, based on the normal vectors b and c of plane DEP and plane FGQ, obtain the angles β and γ between normal vectors b and c and normal vector a, respectively, and adjust plane DEP and plane FGQ so that β and γ are 90°.

[0097] In the three-dimensional model, the position of the plane DEP is adjusted so that when the included angle β is 90°, the normal vector b is perpendicular to the Z-axis of the theoretical three-dimensional coordinate system XYZ. At this time, the normal vector b coincides with the Y-axis of the theoretical three-dimensional coordinate system XYZ. Without changing the actual position of part 15, the alignment of the part on the Y-axis of the theoretical three-dimensional coordinate system XYZ is achieved.

[0098] In the three-dimensional model, the position of plane FGQ is adjusted so that when the included angle γ is 90°, the normal vector c is perpendicular to the Z-axis of the theoretical three-dimensional coordinate system XYZ. At this time, the normal vector c coincides with the X-axis of the theoretical coordinate system XYZ. Without changing the actual position of the part, the alignment of part 15 on the X-axis of the theoretical three-dimensional coordinate system XYZ is achieved.

[0099] Therefore, after the part position is adjusted, the zero point O is taken as the origin, and the directions of the normal vectors a, b, and c are used to determine the X-axis, Y-axis, and X-axis direction, respectively. In the three-dimensional model, a three-dimensional coordinate system XYZ for machining part 15 is established to realize the alignment of the part.

[0100] Specifically, step 2 includes:

[0101] S201: Obtain the distance d between the two X reference planes of the first chuck 601;

[0102] S202: Using the center point of plane D as the detection zero point and the center point of plane F as the measurement point, the distance e from plane F to the zero point is detected and obtained using the probe on the CNC machine tool;

[0103] S203: Obtain the difference between e and 1 / 2d, and determine the center point offset difference f of plane D;

[0104] S204: Based on the offset difference f, adjust the position of plane DEP to obtain plane D′E′P′;

[0105] S205: Obtain the distance r between the two Y-reference planes 4 of the first chuck 601 and the second chuck 602;

[0106] S206: Using zero point O as the detection zero point, on the first chuck 601, with the point on the Y reference plane 4 where the non-plane D is located as the detection point, the distance s between the detection point and the detection zero point is detected and obtained using the probe on the CNC machine tool;

[0107] S207: Obtain the difference between s and 1 / 2r, and determine the offset difference t of the zero point O;

[0108] S208: Based on the offset difference t, adjust the position of plane FGQ to obtain plane F′G′Q′;

[0109] Specifically, in step 3, the intersection of plane ABC, plane D′E′P′ and plane F′G′Q′ is taken as the zero point U, and a new three-dimensional coordinate system X′Y′Z′ is constructed based on the normal vectors a, b and c.

[0110] Compared with the prior art, the present invention adjusts the spatial position of the part during the construction of the three-dimensional coordinate system XYZ to align the part's position. Based on the relative position of the zero point of the constructed three-dimensional coordinate system XYZ with the part, the three-dimensional coordinate system is reconstructed. The reconstructed three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part processing, which overcomes the problem of the zero point O offset affecting accuracy and achieves precise positioning of the part.

[0111] Three small planes are milled on part 15, which has a large external deformation. New planes are reconstructed using the planes containing these three small planes. By adjusting the spatial position of part 15 and the direction of the normal vector of the newly constructed planes, alignment is first achieved in the Z-axis direction of the theoretical coordinate system. Based on this, two new planes are constructed by milling four small planes on the chuck 6 of part 15. Alignment is achieved in the X-axis and Y-axis directions of the theoretical coordinate system using the normal vectors of the two new planes. In this way, even when part 15 has a thin wall thickness and no machining allowance, part 15 can be aligned on a CNC machine tool. Based on the determined three-dimensional coordinate system for machining part 15, the influence of errors in bench scribing can be overcome, thereby improving the machining accuracy of part 15.

[0112] This invention eliminates the traditional scribing method and eliminates the need to level the parts during the first processing step, greatly reducing the labor intensity of the operator.

[0113] Example 1

[0114] A method for precise positioning of thin-walled compartment-type parts includes:

[0115] Step 1: Based on the planes ABC, DEP, and FGQ constructed on the 3D model of the part, construct the 3D coordinate system XYZ for machining part 15, and align the part.

[0116] Specifically, including:

[0117] S101: Mill three planes A, B, and C on one end face of part 15;

[0118] Specifically, three planes A, B, and C are milled out on the end face of part 15 where the chuck is located;

[0119] Among them, the three planes A, B and C are evenly distributed on the end face of the part, and the maximum distance between them is the optimal choice.

[0120] Among them, the dimensions of the three planes A, B, and C are optimally chosen to eliminate errors caused by excessively large areas at the point locations.

[0121] The dimensions of the three planes A, B, and C are φ4mm.

[0122] S102: Mill four planes D, E, F, and G on the chuck 6 of part 15;

[0123] Specifically, including:

[0124] S1021: Plane D and plane E are milled on the sides of the first chuck 601 and the second chuck 602 respectively, and plane D and plane E are parallel to the Y reference plane respectively.

[0125] Among them, the side surfaces corresponding to the two clamps 6 and the side surfaces parallel to these sides are taken as Y reference plane 4, and the direction perpendicular to Y reference plane 4 is taken as the actual X-axis direction based on the part.

[0126] Among them, plane D and plane E are located on the first chuck 601 and the second chuck 602, respectively.

[0127] Furthermore, connect the center points of plane D and plane E, and draw a straight line DE. At this time, the straight line DE is perpendicular to the central axis of the two clamps.

[0128] Furthermore, planes D and E are set adjacent to each other.

[0129] The first chuck 601 and the second chuck 602 have the same structure, and the adjacent surfaces of the first chuck 601 and the second chuck 602 are mirror images. Therefore, it is only necessary to machine planes D and E at the corresponding positions of the adjacent surfaces of the first chuck 601 and the second chuck 602 to make the straight line DE perpendicular to the central axis of the two chucks.

[0130] The straight line DE can be perpendicular to the central axes of the two clamps, or it can intersect perpendicularly.

[0131] Among them, the dimensions of planes D and E should be minimized. If it is not possible to mill small planes, then mill out the smallest measurable features possible to eliminate the error caused by the excessive area of ​​the sampling point.

[0132] The dimensions of planes D and E are both φ2mm.

[0133] S1022: Plane F and plane G are milled on the side of the first chuck 601, and plane F and plane G are parallel to the X reference plane.

[0134] Among them, any plane adjacent to the Y-reference plane 4 is taken as the X-reference plane 5, and the direction perpendicular to the X-reference plane 5 is taken as the actual Y-axis direction based on the part.

[0135] Furthermore, connect the center points of plane F and plane G, and draw a straight line FG. At this time, the straight line FG is perpendicular to the central axis of the first clamp 601.

[0136] Specifically, planes F and G are machined at corresponding positions on the two X-reference surfaces 5 of the first chuck 601. Since planes F and G are mirror-symmetrical, the straight line FG is perpendicular to the central axis of the first chuck 601.

[0137] Furthermore, plane F and plane G are not on the same side of the first chuck 601.

[0138] The straight line FG can be perpendicular to the central axis of the clamp, or it can intersect with it perpendicularly.

[0139] The dimensions of planes F and G are both φ2mm.

[0140] S103: Take a point on part 15 as zero point O, and scan part 15 based on zero point O to establish a theoretical three-dimensional coordinate system XYZ in the three-dimensional model of part 15.

[0141] Specifically, part 15 is clamped on a machine tool and scanned to obtain a three-dimensional model of part 15.

[0142] The position of zero point O satisfies the following conditions: it is on plane ABC and located in the spatial region corresponding to the inner cavity of part 15.

[0143] The theoretical three-dimensional coordinate system XYZ is kept consistent with the three-dimensional coordinate system of the CNC machine tool.

[0144] S104: In the 3D model, construct plane ABC based on the center points of three planes A, B, and C, and obtain the angular offset α of the normal vector a relative to the Z-axis of the theoretical 3D coordinate system XYZ based on the normal vector a of plane ABC.

[0145] Among them, the plane containing the center points of the three planes A, B, and C is called plane ABC.

[0146] S105: Based on the angular offset α, adjust the position of part 15 on the CNC machine tool until the normal vector a coincides with the Z-axis of the theoretical three-dimensional coordinate system XYZ;

[0147] In this process, the position of part 15 is continuously adjusted on a CNC machine tool, and the three-dimensional model of part 15 after each adjustment is obtained to determine the position of normal vector a until normal vector a coincides with the Z-axis of the theoretical three-dimensional coordinate system XYZ.

[0148] In this process, after the position of part 15 is adjusted on the CNC machine tool, its actual position changes, thereby achieving the alignment of the part on the Z-axis of the theoretical three-dimensional coordinate system XYZ.

[0149] Among them, the plane ABC and part 15 are synchronously positioned.

[0150] S106: In the 3D model, construct a new plane DEP based on planes D and E, and construct a new plane FGQ based on planes F and G;

[0151] Specifically, in the 3D model, any plane DEP is constructed through the line DE, and any plane FGQ is constructed through the line FG.

[0152] S107: In the 3D model, based on the normal vectors b and c of plane DEP and plane FGQ, obtain the angles β and γ between normal vectors b and c and normal vector a, respectively, and adjust plane DEP and plane FGQ so that β and γ are 90°.

[0153] In the three-dimensional model, such as Figure 7 As shown, the position of plane DEP is adjusted so that when the included angle β is 90°, the normal vector b is perpendicular to the Z-axis of the theoretical three-dimensional coordinate system XYZ. At this time, the normal vector b coincides with the Y-axis of the theoretical three-dimensional coordinate system XYZ. Without changing the actual position of part 15, the alignment of part 15 on the Y-axis of the theoretical three-dimensional coordinate system XYZ is achieved.

[0154] In the three-dimensional model, the position of plane FGQ is adjusted so that when the included angle γ is 90°, the normal vector c is perpendicular to the Z-axis of the theoretical three-dimensional coordinate system XYZ. At this time, the normal vector c coincides with the X-axis of the theoretical coordinate system XYZ. Without changing the actual position of the part, the alignment of part 15 on the X-axis of the theoretical three-dimensional coordinate system XYZ is achieved.

[0155] After the position of part 15 is adjusted, the origin is taken as zero point O, and the directions of normal vectors a, b, and c are used to determine the X-axis, Y-axis, and X-axis direction, respectively. In the three-dimensional model, a three-dimensional coordinate system XYZ for machining part 15 is established to achieve the alignment of part 15.

[0156] Step 2: Perform midpoint processing on plane DEP and plane FGQ to construct new planes D′E′P′ and F′G′Q′;

[0157] Specifically, including:

[0158] S201: Obtain the distance d between the two X reference planes of the first chuck 601;

[0159] Specifically, on a CNC machine tool, a point on any one X-reference plane 5 is used as the detection zero point, and a point on another X-reference plane 5 is used as the measurement point to detect and obtain the distance d between the two X-reference planes 5.

[0160] The distance d between the two X reference planes 5 is obtained by using a probe, which is a measuring tool installed on the machine tool.

[0161] S202: Using the center point of plane D as the detection zero point and the center point of plane F as the measurement point, the distance e from plane F to the zero point is detected and obtained using the probe on the CNC machine tool;

[0162] The distance e from the zero point to the plane F is obtained by using a probe, which is a measuring tool installed on the machine tool.

[0163] S203: Obtain the difference between e and 1 / 2d, and determine the center point offset difference f of plane D;

[0164] S204: Based on the offset difference f, adjust the position of plane DEP to obtain plane D′E′P′;

[0165] Specifically, if f equals 0, then plane D′E′P′ coincides with plane DEP;

[0166] If f is greater than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f to obtain the plane D′E′P′.

[0167] If f is less than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f in a direction away from the plane, to obtain the plane D′E′P′.

[0168] S205: Obtain the distance r between the two Y-reference planes 4 of the first chuck 601 and the second chuck 602;

[0169] Specifically, on the first chuck 601, the point on the Y-reference plane where the non-plane D is located is taken as the zero point, and on the second chuck 602, the point on the Y-reference plane where the non-plane E is located is taken as the detection point. The distance r between the two Y-reference planes 4 is detected and obtained using the probe on the CNC machine tool.

[0170] S206: Using zero point O as the detection zero point, on the first chuck 601, with the point on the Y reference plane 4 where the non-plane D is located as the detection point, the distance s between the detection point and the detection zero point is detected and obtained using the probe on the CNC machine tool;

[0171] S207: Obtain the difference between s and 1 / 2r, and determine the offset difference t of the zero point O;

[0172] S208: Based on the offset difference t, adjust the position of plane FGQ to obtain plane F′G′Q′;

[0173] Specifically, if t equals 0, then plane F′G′Q′ coincides with plane FGQ;

[0174] If t is greater than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F′G′Q′.

[0175] If t is less than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F′G′Q′.

[0176] Step 3: As Figure 8 As shown, the intersection of plane ABC, plane D′E′P′ and plane F′G′Q′ is taken as the zero point U, and a new three-dimensional coordinate system X′Y′Z′ is constructed based on the normal vectors a, b and c.

[0177] The three-dimensional coordinate system of the CNC machine tool is consistent with the newly constructed three-dimensional coordinate system X′Y′Z′.

[0178] Among them, the newly constructed three-dimensional coordinate system X′Y′Z′ is used as the three-dimensional coordinate system for part machining to overcome the problem of the zero point O offset affecting accuracy. Based on this, the precise positioning of the part is achieved.

[0179] Example 2

[0180] A method for machining thin-walled compartment-type parts, employing the precise positioning method of Embodiment 1, includes:

[0181] Step 1: Fix part 15 on a CNC lathe, and use the positioning method of Example 1 to construct a three-dimensional coordinate system X′Y′Z′ to align the part;

[0182] The first chuck 601 and the second chuck 602 of the part serve as fixed bearing ends and are connected to the clamping device of the CNC machine tool to fix the part on the CNC machine tool.

[0183] Step 2: Set the three-dimensional coordinate system of the CNC machine tool to be consistent with the constructed three-dimensional coordinate system X′Y′Z′, so as to determine the three-dimensional coordinate system for machining and achieve precise positioning of the part;

[0184] Step 3: Based on the machining design requirements, machine the upper surface of part 15;

[0185] Among them, the end face with the first chuck 601 and the second chuck 602 is the upper molded surface, and the corresponding surface of the upper molded surface is the lower molded surface.

[0186] Step 4: Flip the part 180° and use the lower surface of the part as the machining surface for machining;

[0187] Specifically, including:

[0188] S401: After the upper surface of part 15 is machined, rotate the part 180°.

[0189] In this process, the part is rotated 180° around the Y-axis of the three-dimensional coordinate system X′Y′Z′.

[0190] S402: Mill a plane H on the lower surface of part 15, with the intersection of plane H, plane D′E′P′ and plane F′G′Q′ as the zero point U′;

[0191] Among them, plane H is parallel to plane ABC.

[0192] S403: Adjust the position of part 15 so that U′ coincides with U, and construct a new three-dimensional coordinate system XYZ';

[0193] The three-dimensional coordinate system XYZ' is consistent with the three-dimensional coordinate system of the CNC lathe.

[0194] S404: Using the three-dimensional coordinate system XYZ' as the machining three-dimensional coordinate system, the lower surface of part 15 is machined.

[0195] Step 5: After the lower surface of part 15 is machined, rotate the part 180° and remove it from the CNC machine tool.

[0196] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0197] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for precise positioning of thin-walled compartment-type parts, characterized in that, The structure of the thin-walled compartment-like part includes a hollow body with an irregular surface. Two clamps are located on one end face of the body, serving as the fixing part. The method includes: Step 1: Based on the planes ABC, DEP, and FGQ constructed on the 3D model of the part, construct a 3D coordinate system XYZ for part machining, and align the part, specifically including: S101: Mill three planes A, B, and C on one end face of the part; S102: Mill four planes D, E, F, and G on the chuck of the part; S103: Take a point on the part as the zero point O, and based on the zero point O, scan the part to establish a theoretical three-dimensional coordinate system XYZ in the three-dimensional model of the part. S104: In the 3D model, construct plane ABC based on the center points of three planes A, B, and C, and obtain the angular offset α of the normal vector a relative to the Z-axis of the theoretical 3D coordinate system XYZ based on the normal vector a of plane ABC. S105: Based on the angular offset α, adjust the position of the part on the CNC machine tool until the normal vector a coincides with the Z-axis of the theoretical three-dimensional coordinate system XYZ; S106: In the 3D model, construct a new plane DEP based on planes D and E, and construct a new plane FGQ based on planes F and G; S107: In the 3D model, based on the normal vectors b and c of plane DEP and plane FGQ, obtain the angles β and γ between normal vectors b and c and normal vector a, respectively, and adjust plane DEP and plane FGQ so that β and γ are 90°. Step 2: Perform midpoint processing on planes DEP and FGQ to construct new planes D´E´P´ and F´G´Q´, specifically including: S201: Obtain the distance d between the two X reference planes of the first chuck; S202: Using the center point of plane D as the detection zero point and the center point of plane F as the measurement point, the distance e from plane F to the zero point is detected and obtained using the probe on the CNC machine tool; S203: Obtain the difference between e and 1 / 2d, and determine the center point offset difference f of plane D; S204: Based on the offset difference f, adjust the position of plane DEP to obtain plane D´E´P´; S205: Obtain the distance r between the two Y-reference planes of the first and second chucks; S206: Using zero point O as the detection zero point, on the first chuck, with the point on the Y reference plane where the non-plane D is located as the detection point, the distance s between the detection point and the detection zero point is detected and obtained using the probe on the CNC machine tool; S207: Obtain the difference between s and 1 / 2r, and determine the offset difference t of the zero point O; S208: Based on the offset difference t, adjust the position of plane FGQ to obtain plane F´G´Q´; Step 3: Take the intersection of plane ABC, plane D´E´P´ and plane F´G´Q´ as the zero point U, and construct a new three-dimensional coordinate system X´Y´Z´ based on the normal vectors a, b, and c of plane ABC, plane DEP, and plane FGQ; Among them, the three-dimensional coordinate system X´Y´Z´ is used as the three-dimensional coordinate system for part machining.

2. The method according to claim 1, characterized in that: In step S204, If f equals 0, then plane D´E´P´ coincides with plane DEP; If f is greater than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f to obtain the plane D´E´P´. If f is less than 0, then in the 3D model, the plane DEP is moved parallel to the plane F by f in a direction away from the plane F to obtain the plane D´E´P´.

3. The method according to claim 1, characterized in that: In step S208, if t equals 0, then plane F´G´Q´ coincides with plane FGQ; If t is greater than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F´G´Q´. If t is less than 0, then in the 3D model, plane FGQ is moved parallel to plane D by t to obtain plane F´G´Q´.

4. The method according to claim 1, characterized in that: In step S205, on the first chuck, the point on the Y-reference plane where the non-plane D is located is taken as the zero point, and on the second chuck, the point on the Y-reference plane where the non-plane E is located is taken as the detection point. The distance r between the two Y-reference planes is detected and obtained using the probe on the CNC machine tool.

5. The method according to claim 1, characterized in that: Step S102 includes: S1021: Plane D and plane E are milled on the sides of the first chuck and the second chuck respectively, and plane D and plane E are parallel to the Y reference plane respectively; S1022: Plane F and plane G are milled on the side of the first chuck, respectively, and plane F and plane G are parallel to the X reference plane.

6. The method according to claim 5, characterized in that: Plane D and plane E are located on the first chuck and the second chuck, respectively, and are arranged adjacent to each other; plane F and plane G are located on the two X reference planes of the first chuck, respectively. Among them, the side surfaces corresponding to the two clamps and the side surfaces parallel to these surfaces are used as the Y-reference plane, and the direction perpendicular to the Y-reference plane is used as the actual X-axis direction based on the part. Take any plane adjacent to the Y-reference plane as the X-reference plane, and take the direction perpendicular to the X-reference plane as the actual Y-axis direction based on the part.

7. The method according to claim 1, characterized in that: In step S106, connect the center points of plane D and plane E, draw a straight line DE, and construct an arbitrary plane DEP through the straight line DE.

8. The method according to claim 1, characterized in that: In step S106, connect the center points of plane F and plane G, draw a straight line FG, and construct an arbitrary plane FGQ through the straight line FG.

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